Reversal of Endothelial Nitric Oxide Synthase Uncoupling and Up-Regulation of Endothelial Nitric Oxide Synthase Expression Lowers Blood Pressure in Hypertensive Rats

• Published in: Journal of the American College of Cardiology 2006-06, Vol.47 (12), p.2536-2544
• Main Authors: Li, Huige, Witte, Klaus, August, Michael, Brausch, Isolde, Gödtel-Armbrust, Ute, Habermeier, Alice, Closs, Ellen I., Oelze, Mathias, Münzel, Thomas, Förstermann, Ulrich
• Format: Article
• Language: English
• Subjects: Animals; Apolipoproteins; Arterial hypertension. Arterial hypotension; Atherosclerosis; Biological and medical sciences; Blood and lymphatic vessels; Cardiology; Cardiology. Vascular system; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Coronary vessels; Deoxyribonucleic acid; Diabetes; DNA; Endothelium; Endothelium, Vascular - enzymology; Enzyme Inhibitors - therapeutic use; Enzymes; Gene expression; Hypertension; Hypertension - enzymology; Hypertension - prevention & control; Kinases; Laboratory animals; Male; Medical sciences; Nitric oxide; Nitric Oxide Synthase - metabolism; Nitric Oxide Synthase - physiology; Oxidative stress; Protein Kinase C - antagonists & inhibitors; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Rodents; Staurosporine - analogs & derivatives; Staurosporine - therapeutic use; Up-Regulation
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/j.jacc.2006.01.071

Reversal of Endothelial Nitric Oxide Synthase Uncoupling and Up-Regulation of Endothelial Nitric Oxide Synthase Expression Lowers Blood Pressure in Hypertensive Rats Huige Li, Klaus Witte, Michael August, Isolde Brausch, Ute Gödtel-Armbrust, Alice Habermeier, Ellen I. Closs, Mathias Oelze, Thomas Münzel, Ulrich Förstermann Treatment of spontaneously hypertensive rats (SHR) with midostaurin reduced elevated vascular NADPH oxidase expression, diminished reactive oxygen species, enhanced (6R)-5,6,7,8-tetrahydro-L-biopterin, and reversed endothelial nitric oxide synthase (eNOS) uncoupling. Midostaurin also increased vascular eNOS expression, bioactive nitric oxide (NO) in the aorta, and nitrite/nitrate in plasma. Aortas from midostaurin-treated SHR and Wistar-Kyoto rats (WKY) showed an enhanced NO-mediated relaxation; midostaurin lowered blood pressure in SHR, but not in WKY made hypertensive with the NOS inhibitor NG-nitro-L-arginine methyl ester. The reduction of oxidative stress combined with an up-regulation of eNOS gene expression is likely to convey the blood pressure-lowering effect of midostaurin. We sought to examine the hypothesis that a pharmacologic up-regulation of endothelial nitric oxide synthase (eNOS) combined with a reversal of eNOS uncoupling provides a protective effect against cardiovascular disease. Many cardiovascular diseases are associated with oxidant stress involving protein kinase C (PKC) and uncoupling of eNOS. Messenger ribonucleic acid (mRNA) expression was analyzed with RNase protection assay or quantitative real-time polymerase chain reaction, vascular nitric oxide (NO) with spin trapping, and reactive oxygen species (ROS) with dihydroethidium fluorescence. Aortas of spontaneously hypertensive rats (SHR) showed an elevated production of ROS when compared with aortas of Wistar-Kyoto rats (WKY). The aortic expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits (Nox1, Nox2, Nox4, and p22phox) was higher in SHR compared with WKY. In SHR, aortic production of ROS was reduced by the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), indicating eNOS “uncoupling” in hypertension. Oral treatment with the PKC inhibitor midostaurin reduced aortic Nox1 expression, diminished ROS production, and reversed eNOS uncoupling in SHR. Aortic levels of (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4) were significantly reduced in SHR compared with WKY. Midostaurin normalized BH4levels in SHR. In both WKY and SHR,